Most individual users will find the bottle lasts between 1 and 4 months.
If you take a full dose of 2 tsp nightly, the bottle of Calmful Sleep will last at least 20 days.
Most users will find their sleep is dramatically improved at a much smaller dose.
1/2 tsp per night is a good starting point and may never need to be increased, in which case the bottle would last almost 4 months.